Fifty years ago next week, Martin Luther King Jr. stood before a crowd of thousands on the National Mall and called on the nation’s leaders “to open the doors of opportunity” to all Americans.

Dr. King’s “I Have a Dream” speech inspired a generation to act. Five decades later, we are closer to achieving Dr. King’s dream, yet we have not come to realize its full potential. His dream lives on, inscribed not on water but on stone.

The thousands of marchers became one with the millions more who watched, heard or read about it. And in their goodwill and thirst for justice was stored the spark that soon after led to such breakthroughs as the Civil Rights Act and the Voting Rights Act.

Laws alone cannot change hearts. But they can rule rank discrimination out of bounds, and they can nudge us in a better direction. In part because of these laws, attitudes — and behaviors — have steadily and dramatically changed over the years. But we must never take this progress for granted.

Within the lifetimes of millions of present day Americans, many of our citizens were barred from some of Washington’s best hotels. Career paths were blocked. Schools and other public facilities were segregated under the fiction of “separate but equal.” This anniversary reminds us of how far we have come, just as the renewed pressures we are seeing to suppress voting rights reminds us that hard-fought gains can be lost, and must be defended.

Injustice causes damage below the waterline of our republic, and each new generation must take the laboring oar and continue our nation’s journey in perfecting our union. It is our turn.

The Supreme Court’s devastating decision to strike down a key part of the Voting Rights Act must be corrected to protect our fundamental right to vote. Just weeks after the decision, I convened a Senate Judiciary Committee hearing, and I invited Congressman John Lewis to testify. John Lewis was the youngest speaker at the March on Washington five decades ago and is a hero of mine. As someone who fought and bled for the original Voting Rights Act, his testimony about the need to restore the Act was personal and compelling.

I also invited Congressman Jim Sensenbrenner, who I worked with to reauthorize the law in 2006, to testify. The strong words of these two men, a Democrat from Georgia and a Republican from Wisconsin, embodied the rich and bipartisan history of our steady progress toward civil rights. In the coming weeks I plan to introduce legislation to revitalize the Voting Rights Act to protect all Americans against racial discrimination in voting.

The struggle for justice, freedom and equal treatment under the law has always been difficult. We know this in our state. Vermont led the nation in abolishing slavery. And we have stayed true to those guiding principles of fairness and independence by being the first state to provide civil unions for same-sex couples and the first to adopt same-sex marriage through the legislative process. The example of equality set by Vermont contributed to the momentum needed for the Supreme Court’s historic decision overturning Section 3 of DOMA. That decision confirmed my belief that the Constitution protects the rights of all Americans, and it lived up to the motto engraved in Vermont marble above the Supreme Court building that declares “Equal justice under law.”

The continued fight for justice and fairness will also be a part of the Senate Judiciary Committee’s agenda this fall. I will introduce the Second Chance Reauthorization Act to support programs that help state and local authorities successfully reintegrate prisoners into their communities and reduce the rate of repeat offenders. I will convene a hearing on bipartisan legislation to address the use of mandatory minimum sentences, the discredited one-size-fits-all approach to sentencing that is costly and unfair and does not make our country safer.

We should be investing our resources in effective programs like those under the Second Chance Act to prevent crime rather than responding after the fact with overly burdensome sentences that are not effective. I also hope that the House of Representatives will pass legislation to reform our broken immigration system, as we did in the Senate, to provide a pathway to citizenship for those who want to achieve the American Dream.

The anniversary of the March on Washington reminds us of what is possible when people look past their differences and work toward a shared goal. When President Johnson signed the Voting Rights Act into law, he declared: “Through this act, and its enforcement, an important instrument of freedom passes into the hands of millions of our citizens.”

Let us honor those who five decades ago marched on Washington. They inspired our nation to move toward a more perfect union, and they continue to inspire me to fight for equality and justice. They taught us that courage, commitment and action, spun from hope, can accomplish great things.

Let us continue their quest.

Patrick Leahy, Vermont’s senior U.S. senator, is president pro tempore of the Senate and chairs the Senate Judiciary Committee.